CODEWITHSUNDEEP
javahibernatecascade
Jess
Jess

Reputation: 148

Hibernate unable to delete child record

I'm unable to delete a child record while I'm updating (not deleting) the parent record. Also, I've read other posts, but it seems most of the others are using annotations rather than xml, so it can be difficult to see how they relate to my issue.

I have two tables: The EventInfo table that holds information about events and then the EventLicenseType table that only has two columns and both of those columns make up the primary key; one of the columns in the EventLicenseType table is a foreign key to the EventInfo table.

The problem is I can't seem to delete an EventLicenseType record. I've tried a bunch of different things and nothing is working for me. It seems like hibernate wants to put null as the eventinfoId column, which of course doesn't work. I have tried clearing out the Set and then doing the merge, and also specifically calling session.delete(eventlicenseTypeRec) and then doing the merge. Neither is working for me.

EventInfo.hbm.xml file:

<hibernate-mapping default-lazy="true">

<class name="Eventinfo" table="PA_EVENTINFO">
    <id name="eventInfoId" type="int"
        column="PA_EVENTINFOID">
        <generator class="native" />
    </id>
    <property name="eventTypeId" type="java.lang.String"
        column="PA_EVENTTYPEID" length="255" />

        ...Other columns not shown here for brevity...

    <set name="eventLicenceTypeIds" lazy="false" cascade="all-delete-orphan">
        <key column="PA_EVENTINFOID"/>
        <one-to-many class="EventLicenseType" />
    </set>      
</class>

EventLicenseType.hbm.xml file:

<hibernate-mapping default-lazy="true">

<class name="EventLicenseType" table="PA_EVENTLICENSETYPE">
    <composite-id>
        <key-property name="licenseTypeId" type="java.lang.Integer" column="PA_LICENSETYPE"/>
        <key-property name="eventInfoId" type="java.lang.Integer" column="PA_EVENTINFOID"/>
    </composite-id>
</class>

Here is the EventInfo class. Again, there are more fields in the actual file, this is just the important pieces:

public class Eventinfo implements Serializable {
     /** identifier field */
    private int eventInfoId;    

    /** nullable persistent field */
    @Field(name="eventInfo_eventTypeId")
    private String eventTypeId;

    @IndexedEmbedded
    private Set<EventLicenseType> eventLicenceTypeIds;

    /** default constructor */
    public Eventinfo() {}

    public int getEventInfoId() {
        return this.eventInfoId;
    }

    public void setEventInfoId(int eventInfoId) {
        this.eventInfoId = eventInfoId;
    }

    public String getEventTypeId() {
        return this.eventTypeId;
    }

    public void setEventTypeId(String eventTypeId) {
        this.eventTypeId = eventTypeId;
    }

    public Set<EventLicenseType> getEventLicenceTypeIds() {
        return eventLicenceTypeIds;
    }

    public void setEventLicenceTypeIds(Set<EventLicenseType> eventLicenceTypeIds) {
        this.eventLicenceTypeIds = eventLicenceTypeIds;
    }

Here is the EventLicenseType class

public class EventLicenseType implements Serializable{

    @Field
    private int licenseTypeId;
    private int eventInfoId;

    public int getLicenseTypeId() {
        return licenseTypeId;
    }

    public void setLicenseTypeId(int licenseTypeId) {
        this.licenseTypeId = licenseTypeId;
    }

    public int getEventInfoId() {
        return eventInfoId;
    }

    public void setEventInfoId(int eventInfoId) {
        this.eventInfoId = eventInfoId;
    }
}

Here is the method I'm executing in my DAO. For now there is only one record associated to the eventInfo record, so I'm just trying to see if I can delete that one. (Also note that eventinfo is defined in the method that surrounds this one).

public Eventinfo execute(Session session) throws Exception {

    //Get the existing eventInfo record                 
    Eventinfo existing = (Eventinfo)session.get(Eventinfo.class, eventinfo.getEventInfoId());
    Iterator iter = existing.getEventLicenceTypeIds().iterator();
    if (iter.hasNext()) {
        EventLicenseType license = (EventLicenseType) iter.next();
        iter.remove();
        session.delete(license);
    }

    session.flush();

    return (Eventinfo) session.merge(eventinfo);
}

On the above session.flush() line, I get an error: java.sql.BatchUpdateException: Cannot insert the value NULL into column 'PA_EVENTINFOID', table 'PA_EVENTLICENSETYPE'; column does not allow nulls. UPDATE fails. It shows that hibernate is trying to do: 

update PA_EVENTLICENSETYPE set PA_EVENTINFOID=null where PA_EVENTINFOID=?

Why can't it just delete the record? Why is it trying to do an update?? I also tried changing the code to the below and get the same error.

public Eventinfo execute(Session session) throws Exception {

    //Clear out the list
    eventinfo.getEventLicenceTypeIds().clear();             

    return (Eventinfo) session.merge(eventinfo);
}

Can anyone help me with what I'm missing, or point me in the right direction?

Upvotes: 0

Views: 1047

Answers (1)

Anirban
Anirban

Reputation: 949

You need to see whether the mapping between two tables are unilateral or bilateral. Basically you need to think or the rows of two tables as objects and cut all the ties between the objects of EventInfo and EventLicenceType tables. So if the relation is only from EventInfo -> EventLicenseType, you need to set the value of the EventLicenseType set to null in EventInfo object. Also if there is a mapping from EventLicenseType, you need to set the value of joining column to null. Then merge() the EventInfo object.

Noneed to explicitly delete or remove the EventLicenseType object. If here are no references to EventLicenseType object, the JVM will collect it as garbage.

Hope that solves your problem.

Upvotes: 1

Related Questions